Section Ⅷ Grammar
单元语法项目(一)——条件句和混合条件句
语法图解
探究发现
A．①If current Olympic champion Marion Jones took such drugs, she would probably have broken that world record more than once.
②If Peter was a more skillful player, he would have scored more points. B．③Ben Johnson would still be the 100 metres world record holder, if he had not been caught.
④If he had broken that record, he would be a world-famous runner now. [我的发现]
(1)A组句子中，从句表示与现在事实相反的假设，而主句表示与过去事实相反的结果。由此可知混合条件句可以用来谈论“非真实的、常常是想象中的现在状态，可能对过去有影响”，其构成形式是：“if＋主语＋动词的过去式，主语＋would_have_done”。
(2)B组句子中，从句表示与过去事实相反的假设，而主句表示与现在事实相反的结果。由此可知混合条件句可以用来谈论“想象中的过去事件可能对现在有影响”，其构成形式是：“if＋主语＋had_done，主语＋would＋动词原形”。
在英语中，我们一般把条件句分为两种，即真实条件句和非真实条件句。非真实条件句亦可称为虚拟语气。虚拟语气表示说话人的愿望、假设、猜测或建议，而不表示客观存在的事实。
一、if条件状语从句中的虚拟语气
主从句 构成 时态 与现在事实相反 if＋主语＋动词过去式 主语＋if虚拟条件句 主句 1
would/should/could/might＋动词原形 主语＋与过去事实相反 if＋主语＋had＋过去分词 would/should/could/might＋have＋过去分词 if＋主语＋与将来事实相反 动词过去式???were to＋动词原形??should＋动词原形主语＋would/should/could/might ＋动词原形 If I were a bird, I could fly. 如果我是一只鸟的话，我就能飞了。
If we had started earlier, we would not have missed the train. 如果我们早点出发，就不会错过这列火车了。
If he shouldn't come tomorrow, we should put off the meeting till next Monday. 要是他明天来不了，我们将把会议推迟到下周一。
[即时演练1] 用所给动词的适当形式填空
①(2017·北京高考改编)If the new safety system had_been_put (put) to use, the accident would never have happened.
②(湖南高考改编)Sorry, I am too busy now, if I had (have) time, I would certainly go for an outing with you.
③If I were (be) you, I would_go (go) to see the film Lost on Journey. ④If you had_worked (work) hard last year, you would_have_passed (pass) the test.
⑤If she should_come/came/were_to_come (come) tomorrow, I would_ask (ask) her for help.
二、混合虚拟条件句
在虚拟语气中，虚拟条件句与主句所指的时间不一致(如一个是过去的，一个是现在的)，这时主、从句谓语动词的形式需要根据具体的时间来调整，从而构成混合虚拟条件句，即错综时间条件句。该句式中不仅仅存在时间的不同，更重要的是事实和假设的混合，其基本用法如下：
1．想象的过去事件可能对现在或将来有影响
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句子 从句 主句 时间意义 与过去事实相反 与现在/将来事实相反 谓语形式 had done would/should/could/might＋动词原形 If you had taken his advice then, you would be better now. 如果你当时听取了他的建议，你现在会好些。
If you hadn't watched TV late last night, you wouldn't be so sleepy now. 如果你昨晚看电视不看到那么晚，你现在就不会这么困倦。
If I had spoken to him yesterday, I should know what to do now. 假如昨天我对他说了，现在我就知道该怎么办了。 2．想象的过去事件可能对现在正在进行的动作有影响 句子 从句 主句 时间意义 与过去事实相反 与现在正在进行的事实相反 谓语形式 had done would/should/could/might＋be doing If I had studied hard, I would be studying in college now. 如果我努力学习的话，我现在就在大学里学习了。
If he hadn't left for Shanghai, he would be helping me now. 如果他不去上海的话，他现在就帮助我了。
If you had not given me a lift, I would be walking in the rain now. 如果你不让我搭车，我现在还冒雨走着呢。 3．想象中的现在状态可能对过去有影响
句子 从句 主句 时间意义 与现在事实相反 与过去事实相反 谓语形式 动词的过去式(be→were) would/should/could/might＋have done If I were you, I would have gone to watch the Expo then. 如果我是你，当时我就去看世博会了。
If she didn't speak a few languages, she wouldn't have got that job. 如果她不会说几种语言，她就不能得到那份工作了。 [即时演练2] 用所给动词的适当形式填空
①(2016·江苏高考改编)If it had_not_been/hadn't_been (be) for his invitation the other day, I should not be here now.
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2018_2019学年高中英语Unit21HumanBiologySectionⅧGrammar学案含解析北师大版选修7
